Conventionally, graphite rods, such as, for example, fishing rods, have been made from multiple plies of fibers that are wrapped about a mandrel to form a hollow rod. The plies generally comprise an epoxy or other suitable plastic resin that bonds the fibers together, thereby forming an impregnated cloth that is wrapped about the mandrel. The multiple ply rod is generally cured on the mandrel and then removed to form a lightweight, yet durable, hollow fishing rod blank. Typically, the orientation of the fibers of any given impregnated cloth is in one direction, i.e., unidirectional. The unidirectional impregnated cloth is often referred to as a prepreg sheet.
In order to produce rods having reduced weight and increased strength, the prior art teaches several different arrangements of the fiber plies to achieve the desired results. For example, in U.S. Pat. No. 2,749,643, a rod having an outer layer of longitudinally extending glass fiber is shown. The rod has an inner layer of helically wound glass fibers. The outer fibers serve as tension and compression members to resist bending of the rod. The inner layer of glass fibers is described as resisting crushing to provide the rod blank with adequate hoop strength. The provision of adequate hoop strength is important to keep the spacing of the outer layers uniform from the neutral axis to obtain maximum bending resistance.
When tapered hollow rods were introduced using graphite filaments in the inner helically wound layer, the hoop and crush strength were provided by the wound filaments. The outer plies are formed from a pattern sheet having a right triangular shape having parallel, i.e., unidirectional, fibers that are aligned with the longitudinal edge of the pattern. When the outer ply is positioned with the short side of the triangle positioned at the large diameter end of the mandrel and the mandrel is rolled across the outer ply, the mandrel moves more rapidly across the outer ply than does the remainder of the mandrel so that the fibers at the large diameter end progressively increase their angle with respect to the axis of the mandrel as they approach the exterior of the rod. After curing the wrapped mandrel and consolidation of the plies into an integral laminate, the mandrel is removed and a flexible rod remains.
Another class of materials used to form hollow fishing rod blanks are referred to generally as woven materials. Woven materials include fabrics made of the actual fibers, such as, for example, graphite fiber, themselves, which are woven just as fabric for clothing might be. By definition, fabrication of woven materials includes a weaving step. Woven material, or wovens as they are referred to in the art, may have fibers that are oriented in two or more directions to achieve specific results, as opposed to unidirectional orientation achieved using impregnated cloth.
Recently, another class of materials has been developed using a process wherein fibers are bonded together without requiring a weaving step during fabrication. These materials are generally referred to as non-woven materials, or non-wovens. It will be understood that the fibers that comprise the non-woven material have no particular orientation and are generally made by blowing fibers and fusing, or otherwise bonding, the blown fibers together in an essentially random manner. Non-wovens have many desirable characteristics relating to strength and aesthetic appeal. However, non-wovens have not been used in the manufacture of fishing rods or other graphite rod constructions.